XP does not install NETBIOS by default. A client or a domain controller on the network optionally uses the NetBIOS resolver service to query WINS servers, attempting to locate DomainName [1C] entries to complete the logon process. WINS is not installed by default on a 2003 server. I have the same problem, and I have been searching the Internet for answers. I have over 200 XP Pro clients on a Windows 2003 Server Standard. All clients use static IP addressing. I wanted to test Vista on our network. So I installed Vista x64 Ultimate, but I have the same problem everyone else keeps having with the DNS issue. There is an obvious difference in how XP and Vista communicates with DNS, but I have not yet narrowed down the problem. It is a DNS problem on the server, but it is something that I believe needs to be changed to be compatiable with Vista. I haven't found any evidence that it is something you need to change on the Vista client. Most everything I have found points to SRV records, and how they need to be setup versus the "automatic" setup 2003 performs during the wizard.